Founded in 1993 by brothers Tom and David Gardner, The Motley Fool helps millions of people attain financial freedom through our website, podcasts, books, newspaper column, radio show, and premium investing services.

On its last day as a Dow component, Alcoa attempts to be the worst performer of the day.

Although we don't believe in timing the market or panicking over daily movements, we do like to keep an eye on market changes -- just in case they're material to our investing thesis.

As of 12:45 p.m. EDT the Dow Jones Industrial Average (DJINDICES:^DJI) is down 63 points or 0.4%. When we combine today's move with the 40 points the index lost yesterday, Wednesday's "No Taper" rally of 147 points certainly seems a little overblown. The gut reaction of the market to buy on news that the Federal Reserve was not going to take its foot off the gas this month has investors considering what that news really means. Well, first and foremost, it means while the decision to taper didn't happen at this meeting, it will certainly happen sometime in the future. At which point the markets will be forced to deal with interest rates that will certainly rise faster than they are now, meaning more expensive borrowing costs for both businesses and individuals. Which many market participants believe will cause stocks to move lower. Second, it means the Federal Reserve members don't feel the economy is healthy enough to be left on its own at this time. It means the economy is still fragile and could quickly make a turn for the worse if a major problem arose in the near future.

From the way I see it, the no-taper decision is no reason to cheer, and that's what the markets are realizing today and why they are heading south. The S&P 500 is off by 0.39% and the NASDAQ is lower by 0.11%, as the Dow leads all indexes lower.

Speaking of the Dow, this evening Bank of America, Hewlett-Packard, and Alcoa(NYSE:AA) will be replaced on the blue-chip average by Goldman Sachs, Visa, and Nike. This change will have a number of effects on the index, such as changing the general composition as the Dow -- the index will now have four financial institutions, as opposed to three, and an additional global consumer facing retailer. Furthermore, dropping three of the weaker components will significantly change the weighting of all 30 stocks -- especially since two of the three new components will now be two of the three heaviest weighted stocks within the Dow.

As the Dow prepares to make those changes, shares ofAlcoa are down 1.42% on its last day as an index component. The move comes as a senior executive at Russia's Rusal, the world's largest aluminum producer, stated that the world's aluminum supply needs to fall 40%. The executive argues that the reduction is necessary to sustain today's aluminum price. Otherwise, the global price of a metric ton of the metal will continue to fall, making it extremely difficult for the major world aluminum companies to remain profitable. Alcoa has already cut 12.5% of its capacity this year and has announced that it may idle another 11% sometime over during the coming year. Regardless of whether Alcoa is idling plants or selling aluminum below costs, it's hard to see any scenario in which the company grows revenue and profits in the short term.

Another big Dow loser today is Caterpillar (NYSE:CAT), which is off by2.12% after the company released data on its retail sales of machines for August, July, and June. The results, covering all of the company's major regions, were rather terrible, to be blunt. Caterpillar's machine sales worldwide for August fell 10% when compared to August 2012, while July fell 9%, and June dropped 8%. The worst performing region was Asia-Pacific which declined 30% in August, 28% in July, and 21% in June. The best region in August was North America which rose 1%, but had fallen 1% in July and 10% in June. From the looks of things, Caterpillar will likely report a decline in sales when it reports third-quarter results on Oct. 23.

Following its investor conference yesterday, shares of Microsoft(NASDAQ:MSFT) were trading lower by 2.68% this afternoon. The move comes as a number of analyst reported being underwhelmed by the presentations and information they received at the event and that their views of the organization were little changed. Janney's Yun Kim held his "neutral" rating, while Citi reaffirmed its "buy" rating. Jefferies' Ross McMillian said he is encouraged by the company's new organizational structure, but his outlook hadn't changed, nor did his "hold" rating. With all the news coming from Microsoft lately, starting with a reorganization of the company's units, Steve Ballmer's retirement announcement, and the Nokia purchase, investors were hoping for some clarification about what to expect in the coming months. Today's move lower is simply investors displaying their disappointment about the lack of clarity pertaining to these events. Long term investors shouldn't read today's move as a sign of things to come.

Fool contributor Matt Thalman owns shares of Bank of America and Microsoft. Check back Monday through Friday as Matt explains what caused the Dow's winners and losers of the day, and every Saturday for a weekly recap. Follow Matt on Twitter @mthalman5513.

The Motley Fool recommends Bank of America, Goldman Sachs, Nike, and Visa. The Motley Fool owns shares of Bank of America, Microsoft, Nike, and Visa. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.